Conventionally, there is proposed a semiconductor package having a semiconductor chip installed therein. The semiconductor package includes, for example, a first insulation layer, a first wiring layer, an another one of plural insulation layers, and a second wiring layer (see, for example, Japanese Laid-Open Patent Publication No. 2008-306071). The first insulation is formed to seal a circuit forming plane of the semiconductor chip (plane on which an electrode pad is provided) and a side plane of the semiconductor chip. The first wiring layer is layered on the first insulation layer and electrically connected to the electrode pad of the semiconductor chip. Another one of the plural insulation layers is layered on the first wiring layer.
With the conventional configuration of the semiconductor package, the semiconductor chip is only installed in the first insulation layer provided on one side of the semiconductor package with respect to the thickness direction of the semiconductor package. Due to the conventional configuration of the semiconductor package, the conventional semiconductor package has a problem of warping.
More specifically, in a case where silicon is the main component of the semiconductor chip, the thermal expansion of the semiconductor chip is approximately 3.4 ppm/° C. and Young's modulus of the semiconductor chip is approximately 200 GPa. On the other hand, in a case where an epoxy resin is the main component of the first insulation layer or another one of the plural insulation layers, the thermal expansion of the semiconductor chip is approximately 8-150 ppm/° C. and Young's modulus of the semiconductor chip is approximately 0.03-13 GPa. Due to the difference in the value of the physical properties (e.g., thermal expansion, Young's modulus), even though one side of the first insulation layer (the side in which the semiconductor chip is installed) is resistant to deformation due to, for example, thermal stress, the other side of the insulation layer (the side in which the semiconductor chip is not installed), is easily deformed due to, for example, thermal stress. As a result, warping tends to occur on one side of the insulation layer (the side in which the semiconductor chip is installed) at room temperature (for example, approximately, 20-30° C.) in which one side of the insulation layer becomes a protrusion. Further, warping tends to occur on the one side of the insulation layer at a high temperature (for example, approximately (200-300° C.) in which one side of the insulation layer becomes a recess.